JPS61228453A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain practicable excellent sensitivity and durability by incorporating a specified azo pigment in a photosensitive layer. CONSTITUTION:The diazo pigment to be incorporated is represented by formula 1, and embodied by formula 1-1, and as a substituent R, alkyl, aralkyl, aryl, or acyl group is introduced to the N atom of diarylamine forming the skeleton of the diazo pigment of formula 1, thus permitting the polarity of the pigment to be changed, one of carrier generating efficiency and carrier transfer efficiency or both of them to be improved, accordingly, sensitivity of the photosensitive body to be enhanced, and potential stability at the time of uses for a long period to be ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor in which a photosensitive layer contains a specific azo pigment.

[Prior art]

Electrophotographic photoreceptors using inorganic photoconductors such as selenium, cadmium sulfide, and zinc oxide as photosensitive components have been known so far.

On the other hand, since it was discovered that certain organic compounds exhibit photoconductivity, many organic photoconductors have been developed. For example, organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, carbazole,
Low-molecular organic photoconductors such as anthracene, pyrazolines, oxadiazoles, hydrazones, polyarylalkanes, phthalocyanine pigments, azo pigments, cyanine dyes, polycyclic quinone pigments, perylene pigments, indib9 dyes, thioindib Organic pigments and dyes such as No. 9 dye or methine squaric acid dye are known. In particular, organic pigments and dyes with photoconductivity are easier to synthesize than inorganic materials, and the variety of compounds that exhibit photoconductivity in an appropriate wavelength range has been expanded. Organic pigments and dyes have been proposed.

For example, US Pat. No. 4,123,270, US Pat. No. 42,476
No. 14, No. 4251613, No. 4251614, No. 4256821, No. 4260672, No. 4268596, No. 4278747, No. 429
3628, an electrophotographic photoreceptor using a disazo pigment exhibiting photoconductivity as a charge generation substance in a photosensitive layer functionally separated into a charge generation layer and a charge transport layer is known.

An electrophotographic photoreceptor using such an organic photoconductor can be produced by a coating method by selecting an appropriate binder, so it is possible to provide an extremely productive and inexpensive photoreceptor. Although this photoreceptor has the advantage of being able to freely control the sensitive wavelength range through selection, it has poor sensitivity and durability, and so far only a few have been put into practical use.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a novel electrophotographic photoreceptor.

Another object of the present invention is to provide an electrophotographic photoreceptor having practically excellent sensitivity and durability.

[Means for solving problems]

According to the present invention, the following general formula 1, (wherein R represents alkyl, aralkyl, aryl or acyl which may have a substituent, and Ar and Ar2 each represent an aryne or aryl which may have a substituent) Provided is an electrophotographic photoreceptor characterized in that the photosensitive layer contains an azo pigment represented by the following formula (representing a heterocyclic group, and A represents a coupler residue having a phenolic OH group).

In the above general formula (1), the alkyl group is, for example, methyl, ethyl, propyl, butyl, etc., the aralkyl group is, for example, benzyl, phenethyl, naphthylmethyl, etc., and the aryl group is phenyl, diphenyl, naphthyl, etc. Examples of the acyl group include acetyl, propionyl, butyryl, and benzoyl. Examples of substituents that R may be substituted with include hydroxy group, halogen (chloro, bromo, io-1, etc.), furkyl (methyl, ethyl, propyl, butyl, etc.), alkoxy (methoxy, ethoxy, propoxy, butoxy, etc.). ), aryloxy groups (phenyloxy, etc.), substituted amino (dimethylamino, diethylamino, dibenzylamino, pyrrolidino, piperidino, morpholino, etc.), nitro, cyano, acyl (acetyl, benzoyl, etc.), and the like.

Furthermore, as definitions of Ar and Ar2, arylene is, for example, phenylene, biphenylene, naphthylene, anthrylene, etc., and heterocyclic groups are, for example, divalent groups such as benzoxazole, benzothiazole, pyridine, quinoline, thiophene, carbazole, etc. Furthermore, it may be substituted with the above-mentioned substituents.

Further, as the coupler residue having a phenolic OH group of A in general formula (1), for example, the following general formula (
2) to (8): ゛・X-' (In the formula, X is a residue that combines with a benzene ring to form a polycyclic aromatic ring or a heterocycle; R3 and R4 are hydrogen, R5 and R6 each represent an alkyl, aralkyl, or aryl group that may have a substituent; Y is an aromatic hydrocarbon divalent group or forms a heterocyclic divalent group together with a nitrogen atom; R7 represents an aryl or heterocyclic group which may have a substituent; R8 and R9 is alkyl, aralkyl, which each may have a substituent,
aryl or heterocyclic group).

Examples of the polycyclic aromatic ring represented by X include naphthalene, anthracene, carbazole, benzcarbazole, dibenzofuran, benzonaphtho7rane, and diphenylene sulfide. These may be substituted with the substituents described above. In the case of R3°R4, alkyl is, for example, methyl, ethyl, globyl, butyl, etc., aralkyl is, for example, benzyl, 7-enethyl, naphthylmethyl, etc., and aryl is, for example, phenyl, diphenyl, naphthyl, anthryl, etc. Especially R3 is 1 due to limescale.
) Compounds having a structure in which R4 is a phenyl group having an electron-withdrawing group such as halogen, nitro, cyan, or trifluoromethyl at the ○-position are preferred.

These may have substituents. Examples of the heterocycle include carbazole, dibenzofuran, benzimidacylone, benzthiazole, thiazole, and pyridine.

Specific examples of R5 and R6 are the same as those exemplified above for R, and R4. These may be substituted with R substituents as described above.

In the definition of Y, the divalent aromatic hydrocarbon group includes, for example, a monocyclic aromatic hydrocarbon group such as O-phenylene, O-
7-tyrene, perinaphthylene, 1,2-antrylene,
Examples include fused polycyclic aromatic hydrocarbon groups such as 9.10-7 enanethrylene.

Further, examples of forming a divalent heterocycle with a nitrogen atom include a 3,4-pyrazolediyl group, a 2,3-pyridinediyl group, a 4,5-pyrimidinediyl group, and a 6,7-pyrimidinediyl group.
Examples include 5- to 6-membered complex divalent groups such as indazoyA/diyl group, 5,6-penzimimezoldiyl group, and 6,7-chiralindiyl group.

Examples of the aryl group or heterocyclic group for R7 include phenyl, naphthyl, anthryl, pyrenyl, and the like; pyridyl, chenyl, furyl, carbazolyl, and the like. These may be substituted with the substituents described above.

Specific examples of alkyl, aryl, and aralkyl in R8 and R are the same as those listed above. Examples of the heterocycle include carbazole, dibenzofuran, benzimidacylon, benzthiazole, thiazole, and pyridine. These may be substituted with the substituents described above.

Although the present invention is not bound by theory, as a substituent R on the nitrogen atom of the diarylamine that forms the skeleton of the disazo pigment of general formula (1), alkyl, aralkyl,
By introducing an aryl or acyl group, the polarity of the pigment changes, and either or both of the carrier raw nail efficiency and carrier transportability improves, which improves the sensitivity of the photoreceptor and stabilizes the potential during long-term use. gender will be ensured. High sensitivity is thus achieved, making it possible to use high-speed copiers, laser beam printers, and LE
It can be applied to D printers, liquid crystal printers, etc., and stable and beautiful images can be obtained because a stable potential is ensured regardless of the previous history of the photoreceptor.

Representative examples of the disazo pigments used in the present invention are listed below.

(Q
MFN-~I ◆
ψt
ψ3,
↓$
s z S t g JQ S;
; 8 g These disazo pigments can be used alone or in combination of two or more.

In addition, these pigments can be expressed, for example, by the general formula % (where Rt Ar1 t Ar2 in the formula is expressed by the general formula (
1) The diamine represented by the symbols in 1) is tetrazotized by a conventional method, and then the corresponding coupler is coupled in an aqueous system in the presence of an alkali, or the tetrazonium salt of the diamine is converted into a fluoroborate salt. Alternatively, it can be easily produced by once isolating it in the form of zinc chloride double salt, etc., and then coupling it with a coupler in the presence of an alkali in a suitable solvent such as N,N-dimethylformamide or dimethyl sulfoxide. can do.

Next, a typical synthesis example of the disazo pigment used in the present invention is shown below.

Synthesis example (synthesis of the above-mentioned disazo pigment shop 1): 5QQ
Water 80J concentrated hydrochloric acid 16.61/(0,19
mol) and H2N (C) were added thereto, and the mixture was stirred while cooling in an ice-water bath to bring the liquid temperature to 3°C.

Next, add 4.2 PCs of sodium nitrite (0,061 moles) to 7 d of water.
The solution was added dropwise over 10 minutes while controlling the temperature within the range of 3 to 10℃, and after the addition was completed, the solution was added at the same temperature for another 3 minutes.
Stirred for 0 minutes. Carbon was added to the reaction solution and filtered to obtain a tetrazotized solution.

Next, pour 700 d of water into a 2 t beaker and add 21 ml of caustic soda.
After dissolving S' (0.53 mol) naphthol As
(3-Hydroxy-2-naphthoic acid anilide) 16.
1 PC0,061 mol) was added and dissolved.

Cool this coupler solution to 6℃ and adjust the liquid temperature to 6-10'CK.
The above-mentioned tetrazotized solution was stirred under control for 30 minutes, then stirred at room temperature for 2 hours, and further left overnight. After the reaction solution was removed, it was washed with water and filtered to obtain aqueous yeast having a crude pigment content of 20.8 P in terms of solid content. Next 4001
The stirred filtration was repeated four times using 7 N,N-dimethylformamide at room temperature.

Next, after stirring and filtrating twice with 400-methyl ethyl ketone, drying under reduced pressure at room temperature was carried out to obtain a privately made pigment 19.29-
I got it. The yield was 87.

Melting point>250°C Elemental analysis: Calculated value (1) Experimental value (4) C: 74.09 74.05H: 4
．． 64 4.61・N: 12.87
12.85 Although the synthesis method of typical pigments has been described above, other disazo pigments represented by the general formula (1) can be synthesized in the same manner. However, if the solubility of the coupler in an alkaline aqueous solution is low or if the coupling reaction is carried out using a coupler that is easily hydrolyzed, such as the type of coupler represented by the above general formula (7), the coupler may be mixed with DMF.
It is desirable to dissolve the coupler in a solvent such as DMAc and react it with a tetrazonium salt using an organic base such as sodium acetate, pyridine, trimethylamine or triethylamine, while being careful not to hydrolyze the coupler or the reaction solvent.

In a preferred embodiment of the present invention, a disazo pigment represented by the general formula (1) can be used as a charge-generating substance in an electrophotographic photoreceptor in which the photosensitive layer is functionally separated into a charge-generating layer and a charge-transporting layer. The charge generation layer contains as much of the disazo pigment as possible in order to obtain sufficient absorbance and a thin film layer, for example 5 microns, to prevent the generated charge carriers from being trapped within the charge generation layer. Hereinafter, the thin film layer preferably has a thickness of 0.01 micron to 1 micron. This means that most of the incident light is absorbed by the charge generation layer to generate a large number of charge carriers, and that the generated charge carriers are not deactivated by recombination or capture (top f) in the charge transport layer. This is due to the need to inject.

The charge generation layer can be formed by dispersing the above-mentioned disazo pigment in a suitable indulator and coating it on the substrate, or can be obtained by forming a vapor-deposited film using a vacuum vapor deposition apparatus. can.

The binder that can be used to form the charge generating layer by coating can be selected from a wide variety of insulating resins, and can be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, and polyvinylpyrene. Preferably, polyvinyl 1-tyral, polyarylate (such as MaTai combination of bisphenol A and 7-talic acid) f! Recarbonate (Bisphenol A, Z type, etc.) Polyester% Phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide resin, polyamide, polyvinylpyridine, cellulose resin, urethane resin layer, niboxy super resin, casein, polyvinyl alcohol,
Insulating resins such as polyvinylpyrrolidone can be mentioned. The amount of resin contained in the charge generation layer is suitably 80% by weight or less, preferably 40% by weight or less.

The solvent that dissolves these resins is preferably selected from those that differ depending on the class a of the resin, and those that do not dissolve the underlying charge transport layer or sublayer. Alcohols such as isoprono-thenol, ketones such as acetone, methyl ethyl ketone, cyclohexanone, amides such as N,N-dimethylformamide, N,N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, tetrahydrofuran, dioxane, ethylene glycol Ethers such as monomethyl ether, esters such as methyl acetate and ethyl acetate, aliphatic hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, trichloroethylene, benzene, toluene, xylene, Aromatics such as ligroin, monochlorobenzene, dichlorobenzene, etc. can be used.

Coating methods include dip coating method, spray coating method, spinner coating method, heat coating method,
This can be carried out using a coating method such as a Mayer-Perting method, a blade coating method, a roller coating method, or a curtain coating method. Drying is at room temperature. Heat drying is at a temperature of 30°C to 200°C.
It can be carried out stationary or under blown air for times ranging from minutes to 2 hours.

The charge transport layer is electrically connected to the charge generation layer described above, and has the function of receiving and taking charge carriers injected from the charge generation layer in the presence of an electric field and transporting these charge carriers to the surface. have. At this time, this charge transport layer may be laminated on or under the charge generation layer.

When the charge transport layer is formed on the charge generation layer, the substance that transports charge carriers in the charge transport layer (hereinafter simply referred to as charge transport material) is substantially in the wavelength range of electromagnetic waves to which the charge generation layer is sensitive. Preferably, it is non-sensitive. The reason is that the charge transport layer has a filter effect and prevents a decrease in sensitivity. "Electromagnetic waves" referred to here
includes a broad definition of "light rays" that includes r-rays, X-rays, ultraviolet rays, visible light, near-infrared rays, infrared rays, far-infrared rays, and the like.

Charge transporting substances include electron transporting substances and hole transporting substances, and electron transporting substances include chloranyl, pro7anyl, tetracyanoethylene, tetracyanoquinodimethane, 2*4.7-) IJ Nitro-9-fluorenone, 2.4.5.7-tetranitro-9-fluorenone, 2.4.7-) dinitro-9-dicyanomethylenefluorenone, 2.4.5.7-titranitroxanthone, 2.4 There are electron-withdrawing substances such as .8-trinidrothioxanthone and polymerized products of these electron-withdrawing substances.

Examples of hole-transporting substances include pyrene, N-ethylcarbazole, N-isopropylcarbazole, N-methyl-N
-7enylhydrazino 3-methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-3-methylidene-9-ethylcarbazole, N,N-diphenylhydrazino 3-methylidene-10-ethylphenothiazine, N , N-diphenylhydrazino-3-methylidene-10-ethylphenoxazine, P-diethylaminobenzaldehyde-N,N-diphenylhydrazone, P-
Diethylaminobenzaldehyde-N-α-naphthyl-
N-7enylhydrazone, P-pyrrolidinobenzaldehyde-N,N-diphenylhydrazone% 1.3. a
−) ') Me, tylindolenine-ω-aldehyde-
Hydrazones such as N,N-diphenylhydrazone, P-diethylbenzaldehyde-3-methylbenzthiazolinone-2-hydrazone, 2,5-bis(p-diethylaminophenyl)-1,3,4-oxadiazole, 1-
Phenyl-3-(P-diethylaminosteryl)-5-
CP-diethylaminophenyl)pyrazoline, 1-(quinolyl(2)]-3-(p-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, 1-[pyridyl(2):l-a-(p- diethylaminostyryl)-5-CP-diethylaminophenyl)pyrazoline, 1-[6-medoxypyridyl (2)
] -3-(P-diethylaminostyryl)-5-(
P-diethylaminophenyl)pyrazoline, 1-[pyridyl(3))-3-(p-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline,
1-[pyridyl(2)]-3-CP-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, 1-[pyridyl(2)]-3-CP-diethylaminosteryl)-4-methyl-5 -(P-diethylaminophenyl)pyrazoline, 1-[pyridyl (2)
) -3-(α-methyl-P-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline,
1-7E2#-3-(P-diethylaminostyryl)-4-methyl-5-CP-diethylaminophenyl)
Pyrazoline, 1-phenyl-3-(α-benzyl-P-
Pyrazolines such as diethylaminostyryl)-s-(p-diethylaminophenyl)pyrazoline and spiropyrazoline, 2-(P-diethylaminostyryl)-6-diethylaminopenzuoxazole, 2-(P-diethylaminophenyl)-4-(P Oxazole compounds such as -dimethylaminophenyl)-5-(2-chlorophenyl)oxazole, thiazole compounds such as 2-(P-diethylaminostyryl)-6-dinithylaminopenzothiazole, bis(4-diethylamino-2 triarylmethane compounds such as -methylphenyl)-phenylmethane, 1.1-bis(4-N,N --/ethylamino-2-methylphenyl)hebutane, 1.1.2.2-tetrakis(4- Polyarylalkanes such as N,N-dimethylamine-2-methylphenyl)ethane, triphenylamine, stilbene derivatives, polycyclic aromatic compounds having a styryl group, heteroaromatic compounds, poly-N-vinylcarbazole, polyvinylpyrene , polyvinylanthracene, polyvinylacridine, poly-9-vinylphenylanthracene, pyrene-formaldehyde l1jlL
: r-f rucarhasol formaldehyde resin fat.

In addition to these organic charge transport materials, inorganic materials such as selenium, selenium-ternor amorphous silicon, and cadmium sulfide can also be used.

Further, these charge transport substances can be used alone or in combination of two or more.

When the charge transport material does not have film-forming properties, a film can be formed by selecting an appropriate binder. Resins that can be used as binders include, for example, acrylic polyarylates, polyesters, polycarnates (bisphenol A, Z type, etc.), polystyrene, acrylonitrile-butadiene copolymer, polyvinyl butyral, polyvinyl formal, polysulfone, Insulating resins such as polyacrylamide, polyamide, chlorinated rubber, or poly-N-vinylcarbazole, polyvinylanthracene,
Mention may be made of organic photoconductive polymers such as polyvinylpyrene.

Since the charge transport layer has a limit in its ability to transport charge carriers, it cannot be made thicker than necessary. Typically it is 5 microns to 30 microns, with a preferred range of 8 microns to 20 microns. When forming the charge transport layer by coating, an appropriate coating method as described above can be used.

A photosensitive layer having such a laminated structure of a charge generation layer and a charge transport layer is provided on a substrate having a conductive layer. Examples of substrates having a conductive layer include those in which the substrate itself is conductive;
For example, aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium,
Nickel, indium, gold, platinum, etc. can be used, and plastics (for example, conductive material (polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, polyfluorinated ethylene, etc.), or conductive particles (e.g., carden plastic, resin, silver particles, etc.) coated on plastic with a suitable binder, conductive A substrate made of glass or paper impregnated with particles, a plastic containing a conductive polymer, etc. can be used.

A subbing layer having barrier and adhesive functions can also be provided between the conductive layer and the photosensitive layer. Subbing layer, casein,
Polyvinyl alcohol, nitrocellulose, ethylene-
Acrylic acid copolymer, polyamide (nylon 6, nylon 66, nylon 610, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin,
It can be formed from aluminum oxide or the like.

The thickness of the undercoat layer is suitably 0.1 micron to 5 micron, preferably 0.5 micron to 3 micron.

When using a photoreceptor in which a conductive layer, a charge generation layer, and a charge transport layer are laminated in this order, and the charge transport material is an electron transport material, it is necessary to positively charge the surface of the charge transport layer, and exposure after charging is required. Then, in the exposed area, electrons generated in the charge generation layer are injected into the charge transport layer, and then reach the surface and neutralize the positive charge, causing a decrease in surface potential and creating an electrostatic contrast with the unexposed area. . When the electrostatic latent image thus formed is developed with a negatively charged toner, a visible image is obtained. This can be directly fixed, or the toner image can be transferred to paper, glass film, etc. and then developed and fixed.

Alternatively, a method may be used in which the electrostatic latent image on the photoreceptor is transferred onto an insulating layer of transfer paper, then developed and fixed. The type of developer, the developing method, and the fixing method may be any known method or methods, and are not limited to any particular method.

On the other hand, when the charge transport material is made of a hole transport material, it is necessary to charge the surface of the charge transport layer negatively. When exposed to light after charging, holes generated in the charge generation layer are transferred to the charge transport layer in the light path section. It is injected and then reaches the surface to neutralize the negative charges, resulting in attenuation of the surface potential and an electrostatic contrast between it and the unexposed area.

During development, it is necessary to use a positively charged toner, contrary to the case where an electron transport material is used.

Another specific example of the present invention is an electrophotographic photoreceptor containing the above-mentioned disazo pigment and a charge transport material in the same layer. At this time, a charge transfer complex compound consisting of poly-N-vinylcarbazole and trinitrofluorenone can be used in addition to the above-mentioned charge transport substance.

The electrophotographic photoreceptor of this example can be prepared by dispersing the aforementioned disazo pigment and charge transfer complex compound in a polyester solution dissolved in tetrahydrofuran, and forming a film using the resulting coating liquid.

In any photoreceptor, the pigment used is of the general formula (1)
It contains at least one type of pigment selected from the disazo pigments shown below, and its crystal form may be amorphous or crystalline.

In addition, if necessary, a disazo pigment represented by the general formula (1) may be used for the purpose of obtaining a /4' chromatic photoreceptor that increases the sensitivity of the photoreceptor by using a combination of pigments with different light absorptions. It is also possible to use a combination of two or more of the above, or a charge generating substance selected from known dyes and pigments.

The electrophotographic photoreceptor of the present invention can be used not only for electrophotographic copying machines, but also for radar printers, CRT printers, L
It can also be widely used in electrophotographic applications such as ED 7' linters, liquid crystal printers, and radar plate making.

The present invention will be explained below with reference to Examples.

Examples 1 to 4 An ammonia aqueous solution of casein (casein 1
1.2), 28% anthonia water 1 liter, water 222j1
7) was applied with a Mayer bar so that the film thickness after drying was 1.0 microns, and dried.

Next, 5? of the above-mentioned exemplary disazo pigment A1? and butyral resin (butyralization degree 63 mol%) in ethanol 95d.
) 2P was added to the solution and dispersed in a sand mill for 2 hours. This dispersion was applied onto the previously formed casein layer using a Mayer bar so that the film thickness after drying was O.S. microns, and dried to form a charge generation layer.

Next, the hydrazone compound of structural formula 5? and polymethyl methacrylate resin (number average molecular weight 100,000) 55' with benzene 7Q
A photoreceptor was prepared by dissolving the mixture in il and coating it on the charge generation layer using a Mayer par so that the film thickness after drying would be 12 microns, and drying to form a charge transport layer. Azo pigment A1
Instead, photoreceptors of Examples 2 to 40 were prepared in the same manner using the azo pigments shown in Table 1.

The electrophotographic photoreceptor thus prepared was statically charged with corona at -5 kV using Kawaguchi Electric Co., Ltd.'s electrostatic copying paper testing equipment @ Model SP-428, held in a dark place for 1 second, and then charged at an illuminance of 2 lux. The charging characteristics were measured by exposing the sample to light.

The charging characteristics are the surface potential (vo) and the exposure amount Eye (1
ux*aec) was determined. The results are shown in Table 1.

Table 1 Table 1 (Continued) As is clear from the results in Table 1, it was confirmed that the photoreceptor of the present invention had extremely excellent electrophotographic sensitivity.

Examples 41 to 45 Using the photoreceptors used in Examples 1, 3, 4, 17, and 19, fluctuations in bright area potential and dark area potential were measured when used as a repeating body. The method uses a -5.6kV corona charger, an exposure optical system,
The sticker was attached to the cylinder of an electrophotographic copying machine equipped with a developer, a transfer charger, a static elimination exposure optical system, and a cleaner. This copying machine is configured to produce an image on transfer paper as a cylinder is driven. Using this copying machine, the initial bright area potential (vL) and dark area potential (VD) are each -1
The bright area potential (vL) and dark area potential were measured after being set at around 00v and -600v and used 5000 times. The results are shown in Table 2.

Table 2: The photoreceptor of the present invention had extremely good stability in VD and vL even during repeated use.

Example 46 On the charge generation layer prepared in Example 1, 2.4.7-dolinitro9-fluorenone 5? and poly-4,4'-
Dioxysiphaer-2,2'-7'lovancarate (molecular weight 300,000) 5? The coating amount after drying of the coating solution prepared by dissolving the above in 70M of tetrahydrofuran was 10? /- and dried.

The electrostatic charge of the electrophotographic photoreceptor thus prepared was measured in the same manner as in Example 1. At this time, the charging polarity was set to ■. The results are shown in Table 3.

Table 3 vo ■560 Delt E" 5.81 uxesec ■Example 47 A polyvinyl alcohol film having a thickness of 0.5 micron was formed on the aluminum surface of an aluminum vapor-deposited polyethylene terephthalate film.

Next, the azo pigment dispersion used in Example 1 was applied onto the polyvinyl alcohol layer on which the azo pigment dispersion had been formed, so that the film thickness after drying was 0.
It was coated with a Mayer par to a thickness of 5 microns and dried to form a charge generation layer.

Next, the pyrazoline compound of structural formula 5? and polyarylate resin (condensation polymer of bisphenol A and terephthalic acid-yne7.talic acid)5? A solution prepared by dissolving 9 m/l of tetrahydron was coated on the charge generation layer so that the film thickness after drying was 10 microns, and dried to form a charge transport layer.

The charging characteristics and durability characteristics of the photoreceptor thus manufactured vI4 were measured in the same manner as in Examples 1 and 41. The results are shown in Table 4.

Table 4 v: -590V K1%: 4.5 1ux・sec Durability characteristics Initial time After 5000 cycles vDvLvDvL -600V-100V -610V-120V According to the results in Table 4, the photoreceptor of the present invention has good sensitivity; Potential stability during long-term use is also good.

Example 48 An ammonia aqueous solution of casein was coated on an aluminum plate with a thickness of 100 microns and dried to form a subbing layer with a thickness of 0.5 microns.

Next K, 2.4.7-Dolinitro9-Fluorenone5?
and poly-N-vinylcarbazole (number average molecular weight 300
,000)5ii' was dissolved in tetrahydro7rane7Qm() to form a charge transfer complex compound.This charge transfer complex compound and the above-mentioned disazo pigment &(c)1? This dispersion was applied onto the undercoat layer to a dry film thickness of 12 microns and dried.

The charging characteristics and durability characteristics of the photoreceptors thus prepared were measured in the same manner as in Examples 1 and 41. The results are shown in Table 5. However, the charging polarity was set to ■.

Table 5 vo: ■580v EH: 5.3 1ux-aec Endurance characteristics initial time After 5000 sheets durability vDvLvD
vL +610 +105 +625 +1
20 Example 49 The charge transport layer and charge generation layer of Example 1 were sequentially laminated on the casein layer of the aluminum substrate provided with the casein layer used in Example 1, except that the layer formation order was different. A photoreceptor was prepared in exactly the same manner as in Example 1, and the charge was measured in the same manner as in Example 1. However, the charging polarity was set to ■. Charging characteristics are shown in Table 6.

Table 6 vo ■580v

Claims (4)

[Claims] (1) The following general formula 1 ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ (1) (In the formula, R represents alkyl, aralkyl, aryl, or acyl that may have a substituent, and Ar_1 and Ar_
2 represents an arylene or a heterocyclic group which may each have a substituent, and A represents a coupler residue having a phenolic OH group. Photographic photoreceptor. (2) Electrophotographic photoreceptor according to claim 1, in which A in the above general formula is represented by the following general formulas 2 to 8: ▲There are mathematical formulas, chemical formulas, tables, etc.▼(2)▲Mathematical formulas, chemical formulas, tables, etc. ▼ (3) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (4) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (5) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (6) ▲ Mathematical formulas, chemical formulas , tables, etc.▼(7) ▲Mathematical formulas, chemical formulas, tables, etc.▼(8) (In the formula, X is a residue that is fused with a benzene ring to form a polycyclic aromatic ring or a heterocycle; Hydrogen, alkyl, aralkyl, aryl, or heterocyclic group which may have a substituent, or together with a nitrogen atom, form a cyclic amino group; R_5 and R_6 are alkyl, aralkyl, which may each have a substituent; , indicating aryl;
Y is an aromatic hydrocarbon divalent group or forms a heterocyclic divalent group together with a nitrogen atom; R_7 represents an aryl or heterocyclic group which may have a substituent; R_
8 and R_9 each represent an optionally substituted alkyl, aralkyl, aryl or heterocyclic group). (3) The electronic according to claim 1, wherein the photosensitive layer is of a functionally separated type consisting of a charge generation layer and a charge transport layer, and the charge generation layer contains an azo pigment represented by the above general formula (1). Photographic photoreceptor. (4) R_3 in the above general formula (2) is hydrogen,
Claim 2, wherein R_4 is a substituted phenyl represented by the following general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (wherein R_1_0 is a substituent selected from halogen, nitro, cyano, and trifluoromethyl) electrophotographic photoreceptor.